Brakes and motor

I have a 95 S-10 4.3 w/ 125000 miles on it. It is a stick. First I think it might be water in my gas but anyways, a couple of weeks ago it started acting funny on the way home from work, going into first and second it would sputter real bad before actually getting somewhere, I put some "heet" in it, around town it doesn't do to bad now, would this be water in the gas? Also I got my front brakes replaced last summer and every since my brakes act funny (bad). I noticed that it is only when my ABS light is off, so, what I try to do is have to get on the highway and get up to 70mph before it kicks on and I feel safe! At lower speeds it doesn't really give me a problem just only after 45mph then it kind of like jerks as I am trying to slow down. Do you know what could be causing this? Thank you for your time! = )